1. Field of the Invention
This invention relates to surgical fastening apparatus, and specifically to an improved surgical fastening apparatus containing a locking means.
2. Background of the Prior Art
Surgical fastening apparatus for placing gastro intestinal anastomoses are known in the art. Such apparatus are used for suturing gastric and intestinal walls with spaced parallel rows of longitudinally aligned staples or surgical fasteners. For example, Bobrov et al. (U.S. Pat. No. 3,079,606) discloses an instrument for suturing gastric and intestinal walls with metal staples by inserting the tips of the instrument into the lumens of the organs to be sutured through apertures in the walls of the organs. The apparatus comprises a two part frame, each part having finger like projections or forks which are inserted respectively into the apertures in the walls of the organs to be sutured. The frame parts are hinged together with the body tissue held between the forks. When the instrument is actuated, longitudinally moving cam bars contact staple drive members in one of the forks, thereby pushing the surgical staples through the body tissue and into an anvil in the opposite fork. A knife blade between the cam bars creates an incision between the parallel rows of staples. It should be noted, however, that the knife blade is an optional feature. The instrument may be used to fasten body tissue without creating an incision between the rows of staples.
Green et al. (U.S. Pat. No. 3,490,675) discloses an improved instrument of type discussed above, the improved instrument laying down double rows of staples on each side of the incision.
A further improvement in this type of instrument is disclosed in Green (U.S. Pat. No. 3,499,591). The further improved apparatus incorporates an improved structure for the staple-containing cartridge, the pusher assembly which includes the cam bars and knife, and the staple driving members. The contents of the above mentioned patents are incorporated by reference herein in their entirety.
Generally, the instruments discussed above are successfully used in abdominal, gynecological, pediatric and thoracic surgery for resection, transection and creation of anastomoses. However, there is a danger during an operation that the surgeon may inadvertently insert the forks of the instrument into body organs when the instrument is empty of staples. This can occur when the instrument has already been fired but not reloaded or discarded. Under such circumstances, the cam bar and knife blade can be moved, thereby creating an unsealed incision, and causing blood loss and trauma to the patient undergoing the surgery. Non-cutting fasteners, i.e., those without the optional knife mechanism, are also commonly used to seal incisions, for example, in transactions in which the surgeon uses a scalpel to manually create an incision on the outside of the rows of staples. Consequently, the danger of using an empty fastener applies equally to both cutting and non-cutting fasteners. The surgical fastening apparatus mentioned above do not possess means for preventing the problem of reactuation of an apparatus which is empty of staples.
To eliminate these dangers it is beneficial to have a locking mechanism which will allow a single use, but which will prevent the surgical stapler from being inadvertently fired more than once.